Presently, coiled tubing unit within 2 in-6,000 m specification are matured domestically and abroad, form a variety of structural types including vehicle-mounted structure, skid-mounted structure, and trailer-mounted structure, and can meet the requirements for use in different regions. However, the coiled tubing unit which can hold coiled tubing above 2 in-6,000 m specification or 2 in-8,000 m specification are only available in a smaller number of countries such as USA and Canada, etc., but are not used in China and many other countries and regions yet. Such coiled tubing unit usually use a semi-trailer-mounted structural type, and some of them use an all-in-one trailer-mounted structure (i.e., all devices are disposed on a semi-trailer) to reduce the number of vehicles required for transportation. Consequently, the vehicles are in a large overall size, extra high, extra wide, and extra heavy. For instance, the 2 in-7,600 m coiled tubing unit from National Oilwell Varco (NOV) is in 5 m height and 33 m length. Such coiled tubing unit can be used in regions where the road conditions and transportation regulations permit, but can't be used in countries and regions where the road conditions are limited or the transportation regulations forbid. For example, in China, the road transportation regulations specify that general-purpose transportation vehicles shall be in width≤2,550 mm and in height≤4,000 mm and special over-limit transportation vehicles shall be in width≤3,000 mm and in height≤4,500 mm. Moreover, vehicles in extra-large dimensions have higher requirements for well fields, and can't be used in well fields where the space is limited.
Hence, there is a demand for a coiled tubing unit, which can meet the requirements for transportation in regions where smaller vehicle dimensions and weight are specified for transportation when coiled tubing in large diameter and/or great length is transported, and is adaptive to the habits of operation and can be deployed flexibly so that it can be used in a well field where the space is limited.